ALL CIE PHYSICS DOUBTS HERE !!!

[Dania]

Energy= mgh
The distance is halved
And the mass is also halved, because half move into the other vessel
so mgh/4

So silly of me. Thanks!

[Deadly_king]

I need help with the following pls
W06 Q25
S06  Q9 & Q33
S07 Q23
W07 Q35
S08 Q6 & Q12
W09 P11 Q17 Why is it C and not D
Sorry for all the questions but these are all i have, thanx for any help, rly appreciated

Nov 06 No 25
From X to Y, there is 1.5 cycle. This implies that X is 1.5T ahead of Y.

T is taken to be 2pie.

Phase difference = 1.5 x 2pie = 3pie. Hence n = 3.

Answer is C

Jun 06 p1

9. It says that the object moves up and down. So initially it is found at the bottom from where it is released. It's velocity increases until it passes the equilibrium position and then decreases to zero when it reaches its maximum at the top. This is point B.

The question asks the velocity at the lowest point of the motion.
Lowest point => V = 0ms^-1
Since B shows the highest point, D is bound to be the answer. As the ball comes back to its initial lowest position, its velocity comes back to zero.

Answer is D

33. A p.d of 12V is applied across P and Q. This implies p.d across both PXQ and PYQ is 12V since they are connected in parallel.

We need to find p.d in each resistor.
Along PXQ, p.d across 500 Ohm resistor is given by R₅₀₀/R_total x p.d
p.d acorss 500 Ohm resistor will be 500/1500 x 12 = 4V. Therefore p.d across 1000 Ohm resistor will be (12 - 4) = 8V

Use the same formula(in bold) and you'll find p.d across 2000 Ohm resistor to be 8V while that across 1000 Ohm resistor to be 4V.

Hence p.d across X and Y = 8 - 4 = 4V (using either 500 and 2000 Ohms resistor or the two 1000 Ohms resistor)

Answer is B

Jun 07 No 23

Am not sure about the explanation. So i'll proceed by elimination.

A : The speed is maximum at P -----> False since at maximum positions v= 0 ms^-1.

B : The displacement at Q is always zero -----> this is not true since it is zero only at that instant. It will increase or decrease in other cases.

C : The energy at R is entirely kinetic. ----> At maximum or minimum positions, energy is rather entirely potential and zero kinetic.

D : The acceleration at S is maximum. -----> Magnitude of acceleration should have been constant throughout the wave. Constant but maximum.

I find D as the most appropriate answer but am not sure if the reason I provided for D is valid.

Answer is D

Nov 07 No 35
From diagram 1, we can note that both the voltmeter and the battery are connected in parallel to the system of resistors.

This is also the case in diagram 2. Both the voltmeter and the battery are still connected in parallel to the system of resistors. So both diagrams are the same and will have same readings.

Voltmeter reading is zero since all resistors being  identical will draw same amount of voltage. Hence p.d will come out to be zero.

Answer is A

Jun 08 p1

6. Acceleration is always perpendicular to its motion => Here we are talking about centripetal acceleration.

Hence speed remains constant but the velocity is said to be continuously changing since its direction changes. However its magnitude is constant.

Answer is C.

12. Using Newton's 2nd law of motion.
Resultant force = ma
Driving force - Resistive force = ma
2000 - F_r = 750(2) -----> F_r = 500 N or 0.5 kN

Answer is A

Nov 09 p11 No 17

Nope. It can't be D since ice is a solid and has a compact shape with strong intermolecular forces of attraction between its molecules. Therefore they won't be having same potential energies. So total energies won't be the same either.

The answer is C because K.E is proportionl to temperature and both the water and the ice are at 0^oC.

Hope it helps

[cs]

Thanks Deadly King, done with the exam. =)

[Deadly_king]

Thanks Deadly King, done with the exam. =)

Glad that you're over.

No discussions please because i've not yet sit for it

[TJ-56]

Nov 06 No 25
From X to Y, there is 1.5 cycle. This implies that X is 1.5T ahead of Y.

T is taken to be 2pie.

Phase difference = 1.5 x 2pie = 3pie. Hence n = 3.

Answer is C

Jun 06 p1

9. It says that the object moves up and down. So initially it is found at the bottom from where it is released. It's velocity increases until it passes the equilibrium position and then decreases to zero when it reaches its maximum at the top. This is point B.

The question asks the velocity at the lowest point of the motion.
Lowest point => V = 0ms^-1
Since B shows the highest point, D is bound to be the answer. As the ball comes back to its initial lowest position, its velocity comes back to zero.

Answer is D

33. A p.d of 12V is applied across P and Q. This implies p.d across both PXQ and PYQ is 12V since they are connected in parallel.

We need to find p.d in each resistor.
Along PXQ, p.d across 500 Ohm resistor is given by R₅₀₀/R_total x p.d
p.d acorss 500 Ohm resistor will be 500/1500 x 12 = 4V. Therefore p.d across 1000 Ohm resistor will be (12 - 4) = 8V

Use the same formula(in bold) and you'll find p.d across 2000 Ohm resistor to be 8V while that across 1000 Ohm resistor to be 4V.

Hence p.d across X and Y = 8 - 4 = 4V (using either 500 and 2000 Ohms resistor or the two 1000 Ohms resistor)

Answer is B

Jun 07 No 23

Am not sure about the explanation. So i'll proceed by elimination.

A : The speed is maximum at P -----> False since at maximum positions v= 0 ms^-1.

B : The displacement at Q is always zero -----> this is not true since it is zero only at that instant. It will increase or decrease in other cases.

C : The energy at R is entirely kinetic. ----> At maximum or minimum positions, energy is rather entirely potential and zero kinetic.

D : The acceleration at S is maximum. -----> Magnitude of acceleration should have been constant throughout the wave. Constant but maximum.

I find D as the most appropriate answer but am not sure if the reason I provided for D is valid.

Answer is D

Nov 07 No 35
From diagram 1, we can note that both the voltmeter and the battery are connected in parallel to the system of resistors.

This is also the case in diagram 2. Both the voltmeter and the battery are still connected in parallel to the system of resistors. So both diagrams are the same and will have same readings.

Voltmeter reading is zero since all resistors being  identical will draw same amount of voltage. Hence p.d will come out to be zero.

Answer is A

Jun 08 p1

6. Acceleration is always perpendicular to its motion => Here we are talking about centripetal acceleration.

Hence speed remains constant but the velocity is said to be continuously changing since its direction changes. However its magnitude is constant.

Answer is C.

12. Using Newton's 2nd law of motion.
Resultant force = ma
Driving force - Resistive force = ma
2000 - F_r = 750(2) -----> F_r = 500 N or 0.5 kN

Answer is A

Nov 09 p11 No 17

Nope. It can't be D since ice is a solid and has a compact shape with strong intermolecular forces of attraction between its molecules. Therefore they won't be having same potential energies. So total energies won't be the same either.

The answer is C because K.E is proportionl to temperature and both the water and the ice are at 0^oC.

Hope it helps

Thank you so much Deadly King! +rep (need to spread the love but i owe u one)

Thank u all for ur help

>GOOD LUCK TO EVERYONE<

[Deadly_king]

Thank you so much Deadly King! +rep (need to spread the love but i owe u one)

Thank u all for ur help

>GOOD LUCK TO EVERYONE<

Anytime dude

Hope you manage well in the exams.

[$!$RatJumper$!$]

Well i guess im done with this topic in the forums here I have learnt so much here its unbelievable! Thank you all so much for all the help... every question i asked was answered by someone and im really grateful for that

Thank guys and best of luck in your other subjects

[Deadly_king]

Well i guess im done with this topic in the forums here I have learnt so much here its unbelievable! Thank you all so much for all the help... every question i asked was answered by someone and im really grateful for that

Thank guys and best of luck in your other subjects

Hehe..............it has been a pleasure to clear your doubts and help you in your studies.

I just hope that now that your exams are over, you're not going to leave SF.

I don't know if you've noticed but we're going to have kinda festival on the occasion of Halloween. It would be really nice if you all participated.

This is an event where most if not all members of SF are invited.

Here is the link if you need any details.

[$!$RatJumper$!$]

Oh no ofcourse not im still here Plus i have Chem p1 to still do lol
Festival sounds gr8!

[Ivo]

Some very difficult extension questions on projectile motion, I'll be very impressed if anyone can get these:

1) A golf ball is hit at 60ms^-1.  At what angle should it leave the club in order to travel 250m horizontally?  You will need to use the double angle formula .

2) Prove that, in the absence of air resistance, the maximum range of any projectile is achieved when it is launched at 45^o to the horizontal.

3) How can two projectiles launched with the same speed but at different angles have he same range?

[elemis]

Small question : when a projectile is thrown upwards.... at the top/apex of its motion does it have only potential energy OR KE and PE ?

[Hypernova]

Small question : when a projectile is thrown upwards.... at the top/apex of its motion does it have only potential energy OR KE and PE ?

When a projectile is throw directly upwards it comes to an instantaneous rest at the apex. Since KE=1/2mv², and v=0, it has no KE at the apex, just PE.

Its different if it was thrown at an angle

[elemis]

When a projectile is throw directly upwards it comes to an instantaneous rest at the apex. Since KE=1/2mv², and v=0, it has no KE at the apex, just PE.

Its different if it was thrown at an angle

Thanks. Just wanted to confirm.

How would it be different ?

[Deadly_king]

Thanks. Just wanted to confirm.

How would it be different ?

This is because it will still have a horizontal component of velocity. Only the vertical component will be zero.

So it's going to have P.E as well as K.E

[elemis]

This is because it will still have a horizontal component of velocity. Only the vertical component will be zero.

So it's going to have P.E as well as K.E

Yeah, I knew that. Thanks guys.

+rep to both of you.